The Norwegian tragedy is just that, a tragedy. It does not signify anything and should not be forced to do so. A man so insane he can see nothing wrong in shooting dead 68 young people in cold blood is so exceptional as to be of interest to criminology and brain science, but not to politics. We can sympathise with the bereaved, and with their country in its collective sense of loss. But the tragedy does not signify.

No, Anders Breivik does not tell us anything about Norway. No, he does not tell us anything about "the state of modern society". He tells us nothing about terrorism or gun control or policing or political holiday camps. His avowal of fascism could as well have been of communism or Islamism or anarchism. The desperate, perhaps understandable, search to find meaning in such acts is dangerous. Breivik does not even measure up to the ideological coherence of the nazism he admired. He is plainly very sick.

David Cameron was therefore wrong to leap forward and order "a review of the far right", or of the far anything. The hysteria of the moment may require a knee jerk from those in power, but why the national security council was summoned, or "a review of our security at home" needed, is a mystery. To the victims, the killings were an act of random madness, a terrible accident, a car crash, a catastrophe out of the blue. To seek normality in their abnormality only gives them currency, and probably spurious meaning.

Worst of all has been the confusion of language. That a mass murderer might like to parade as a jihadi, a holy warrior or a Knight Templar does not make him one. That he does something terrible does not make him a terrorist. Cameron's reference on Monday to Britain having also been a victim "of horrific acts of terrorism" made precisely the linkage that Breivik might have wanted.

Terrorism is a specific and rational political form: the use of violence to achieve a multiplier of fear through a civilian population to a particular end. Visiting "shock and awe" by bombing Baghdad in 2003 was terrorism, as were the bombs on the London Underground. Killing Norwegian teenagers (not Muslims) to express some vague hatred for society is not. It is merely deranged.

Nor can I see any purpose in detailed textual analysis of Breivik's so-called manifesto, least of all as a means to make easy partisan points, leftwing or rightwing, out of its garbled horror. We do not need a mass killing in Norway to know that the English Defence League and British National Party are distasteful and xenophobic organisations. The "experts in far-right studies" emerging from British universities to suggest "possible links" merely feed the hysteria, publicising what is best ignored.

No system of security can prevent such incidents. Norway, like Britain, has tough anti-gun laws; its excellent community policing should in theory throw up early warning of antisocial personalities. Like the rest of Scandinavia, it boasts an obsessive "health and safety" culture. But nothing is fool-proof. To demand ever more control of the sale of weapons and ever more espionage of fringe political groups may serve the interest of the security industry in bidding for power and money. But it also puts pressure on government to impose ever more monitoring and surveillance. This sows fear and induces deference to authority. Is that the outcome we want?

Was it pure coincidence that on Monday the government told parliament that it was quietly breaking its clear post-election promise to destroy the stored DNA of people arrested but not charged? This was an outrageous, unjustified, police-lobbied reneging on a central libertarian principle, to which both coalition parties were committed. It is tempting to think that modern British governments will use any excuse to further illiberal repression. This announcement passed almost unnoticed by the press, while editorials were devoted to telling Norway to "show courage and resilience" and "stand up for freedom" in the face of Breivik's attack.

Norway has no need of such admonition. While it might appreciate the world sharing in its collective grief, it can reply that Norway is one of democracy's more alert champions. Nor is it casual or uncritical in its championship.

In 2004 Norway celebrated a century of independence, not with fireworks and self-congratulation but a voluminous study of its constitution's health. It took five years and yielded 50 books, forming an astonishing Domesday survey of democracy in one country. Like apiarists round a beehive, scholars studied every minute facet of political life and party affiliation, every local association, newspaper, lobby and minority group.

The majority of the scholars reached the conclusion that their country's "democratic infrastructure" was in urgent need of repair. The traditional "chain of command", from voters and localities to decisions of central government, had eroded. With just 4.9 million people – a population smaller than Scotland's – Norway faced being run by a self-perpetuating oligarchy of Oslo officials, bankers, lawyers and media. They would be overseen by an ineffective rolling coalition of politicians elected under proportional representation and thus rarely out of office. Norway, since the advent of its oil wealth, was in danger of becoming a nation too comfortable to worry about politics. Democracy was suffering not from a lack of social cohesion but perhaps from too much.

The UK interpreter of the Norway study, the Oxford political scientist Stein Ringen, drew from it a controversial set of messages (reported in the TLS in April 2004). They included reform of proportional representation, which was neutering decisive elections; stopping subsidies to political parties, which cut them off from their members; withdrawing from Europe's legal conventions, to make Norway's parliament directly responsible for human rights; welcoming, not suppressing, multiculturalism; and rebuilding local democracy, which was active not passive.

Norway has yet to implement many of these suggestions. But their vitality shows it can debate them, and needs no patronising from more "mature" democracies, least of all ones that react to every threat with another turn of the illiberal screw. If the world is to put Norway in the spotlight, the lesson it should draw is that advocated at the weekend by its prime minister, Jens Stoltenberg, for more openness and pluralism. Vigorous argument, not witch-hunts and repression, is the way to entrench democracy, rather than overreacting to a terrible but random act of insanity.